#75 Add one of this common used CAD Filetype: STEP, IGES, SAT, x_t

[Premtoni]

For using CAD Programs
See Attachement I added the same model in many Filetype.

STEP:
http://en.wikipedia.org/wiki/STEP-File
http://en.wikipedia.org/wiki/ISO_10303

SAT:
http://en.wikipedia.org/wiki/SAT_file

IGES:
http://en.wikipedia.org/wiki/IGES

x_t:
http://en.wikipedia.org/wiki/.x_t
http://www.plm.automation.siemens.com/en_us/products/open/parasolid/index.shtml